Pipe or tube bending machine



P. MUELLER ET AL PIPE 0R TUBE BENDING MACHINE March 9 1926 Filed March 16, 1922 12 Sheets-Sheet 1 o o a. 0

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P. MUELLER ET AL PIPE 0R TUBE BENDING MACHINE March 9 1926.

Filed March 16, 1922 12 Sheets-Sheet 2 Pjfaeller, amLvcas, & JZC. 50.6

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March 9 1926. 1,575,928

P. MUELLER ET AL PIPE OR TUBE BENDING MACHINE Filed March 16, 1922 12 Sheets-Sheet 5 III I avwenm .Mueller; all/.Lucaa;

March 9 1926.

P. MUELLER ET AL PIPE OR TUBE BENDING MACHINE Filed March 16, 1922 12 Sheets-Sheet 4 VE N TOPS 6. Sckaermaun W Ml" a Q (1822a PMzzelle 7; a WLuca March 9 1926.

P. MUELLER ET AL PIPE OR TUBE BENDING MACHINE Filed March 16, 1922 12 Sheets-Sheet 5 I N VEN TORS izl P. MUELLER ET AL PIPE OR TUBE BENDING MACHINE Margh 9 1926.

Filed March 16, 1922 12 Sheets-Sheet 6 x x a INVENTOR.

12 Sheets-Sheet P. MUELLER ET AL Filed March 16, 1922 PIPE OR TUBE BENDING MACHINE INVENTOR. 71 11462167; 63713111605 Burk 9.0. 'ekuermarm TTORNEYJ March 9 1926.

March 9 1926.

P. MUELLER ET AL PIPE OR TUBE BENDING MACHINE Filed March 16, 1922 12 Sheets-sheaf 8 INVENTOR. BMUeZZer, GWbucas, BY (54 flCrJ'cfic/er'mann.

March 9 1926.

P. MUELLER ET AL PIPE 0R TUBE BENDING MACHINE 12 Sheets-Sheet 9 Filed March 16, 1922 Q ./-7. Schliemann INVENTOR.

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March 9 1926.

P. MUELLER ET AL PIPE OR TUBE BENDING MACHINE Filed March 16, 1922 12 sheets-s e t 10 INVENTOR. PHueZZer, GWLucaaj P. MUELLER ET AL PIPE 0R TUBE BENDING MACHINE March 9 1926.

Filed March 16, 1922 12 Sheets-Sheet 1 1 March 9 1926.

P. MUELLER ET AL PIPE OR TUBE BENDING MACHINE a mom 1 $01, M11166; $14 615kwzwazma l2 Sheets-Sheet 12 fifille/ZPZ: 6

Filed March 16, 1922 Patented Mar. 9, 1926.

UNITED STATES PATENT OFFICE.

PHILIP MUELLER, CLARENCE WaLUGAS, AND ANTON G. SCHUEEMANN, OF DECATUR, ILLINOIS, ASBIGNOBS TO ADOLPH MUELLER, TRUSTEE, OF DECATUR, ILLINOIS.

IPIPE OR TUBE BENDING MACHINE.

Application filed latch 10, 1022. serial N'o. 544,133.

' To all whom it may comm:

Be it known that PHILIP MUELLER, CLAR- ENoE W. LUCAS, and ANTON C. SGHEUR- MANN, citizens of the United States, residing at Decatur, in the county of Macon and State of Illinois, have invented new and useful Improvements in Pipe or Tube Bending Machines, of which the following is a specification.

The resent invention relates to improvements 1n machines for bending pipes or tubes, and particularly for bending metal tubes having thin walls.

Machines of the character or type to which the'invention relates are extensively used for bending tubes or pipes to any desired angle, up to 180, on a small radius in the manufacture of bent tube traps for plumbing fixtures and other purposes.

Heretofore, in the bending of thin wall tubes for the purposes noted, it has been necessary to employ two different machines to complete the bending operation. That is, during the initial bending of the tube or pipe, it was somewhat flattened in cross section on the outer periphery of the bend, and in order to restore the normal cross sectional form of the tube it has been necessary to employ a. second machine acting upon such flattened portion.

By the machine of the present invention a tube or pipe may be, at a single operation, bent to the desired extent, and all portions of the finished product be of the proper or normal cross sectional form.

The invention also relates to a novel method by which it is possible to produce bent pipes or tubes in which the Wall of the bent portions will not be materially thinner than the other sections.

With these and other objects in view, the invention resides .in the novel method that will be hereinafter described and the construction and arrangement of parts illustrated in the accompanying drawings and set forth in the appended claims.

In the accompanying drawings, which illustrate an embodiment of the invention Figure 1 is a plan view. Fig. 2 is a side elevation. Fig. 3 is a transverse vertical section. Fig. 4 is a horizontal section substantially on the line 44 of Fig. 3.

Fig. 5 is a vertical sectional view of the upper portion of the machine substantially on the line 55 of Fig. 1. I

.,F1g. 5 is a detail vlew, being a transverse vertical section substantially on the lines of Figs. 1 and 5, of the tube clamping aws.

Fig. 6 is a section on the line 66 of Fig. 1 showing the tube clamped in position prior to the bending operation.

Fig. 7 is a view on the line 7-7 of Fi 1 with the parts in the position assumed w en the tube has been bent.

Fig. 8 is a section on the line 8-8 of Fig. 1.

Fig. 9 is a plan, partly in section, on a slightly enlarged scale, of the tube clamping and bending means, showing the parts in the initial position prior to bending.

Fig. 10 is a similar view showing the position of the parts when the bending operation has been completed.

4 Fig. 11 is an enlarged detail plan of a portion of the automatic means for controlling starting of the mandrel withdrawing devices.

Fig. 12 is a sectional view substantially on the line 1212 of Fig. 11'.

Figs. 13 to 15 are severally a plan, side elevation partly in section, and a transverse section of the flexible portion of the bending mandrel.

Figs. 16 and 17 are details of portions of the brake mechanism.

Figs. 18 and 19 are detail views of the normally operative lock for the starting lever.

Fig. 20 is a view of parts shown in Figures 18 and 19, showing the starting lever in locked position.

Fig. 21 is a detail view illustrating in full lines a section of tube prior to its being bent by the machine and according to the method of the present invention, and in dotted lines the relative change effected by the bending operation.

Figs. 22 and 23 illustrate the slight flattening of the tube that occurs during the bendby withdrawing the mandrel from the tube. Figs. 24 to 28 illustrate a slightly modified fornr of mandrel.

Referring to the drawings, the machine is 7 ing operation and how the same is removed supported b a suitable pedestal comprising a base 1, an upwardly extending side members 2, 2, connected by a web or connecting portion 3 which is suitably apertured to receive the main ower shaft, hereinafter more particularly re erred to.

A vertical shaft 4 is mounted in bearings on the web'3 of the supporting pedestal and to the lower portion 0 this shaft is suitably secured a worm gear 5 with which meshes a worm 6 mounted on the main power shaft 7 that is supported in bearings carried by the pedestal and a bracket arm 8 that extends laterally from the edestal, being securely bolted to the base p ate 1.

The shaft 4 extends abovethe u per end of the supportin pedestal and on t e upper end of said shai t is secured the carrier by which the tube bending devices are directly supported.

As shown, this carrier comprises a disklike member 9 to which are connected the members 10, 11 of a tube clamp. The member 10 is adjustably mounted on the carrier 9, but is held relatively stationary thereon, while the member 11 is adapted to be moved bodily toward and from the relatively stationary clamp member 10, being held in position to firmly grasp a tube between said members when the machine is being operated.

As shown, the tube clamping jaws 10, 11, are carried by a plate 12, which is mounted on the disk-like carirer 9, and in order that the machine may be adapted for treating tubes of different diameters the clamps 10, 11, are removably connected to said plate.

In the embodiment of the invention illustrated, the plate 12 is provided with slots 12, 12*, 12, through which pass suitable bolts that serve to connect the plate 12 to the carrier 9, said bolts also holding the tube clampin member 10 in position. The adjustable tu e clamp member 11 is connected with the plate 12 by guide bolts 29 that extend from said clamp member into cpuntersunk slots 12 in the plate 12 (see Fig. 6), and said clamp member is moved into engagement with the tube to be bent and into operative relation to the relatively stationary clamp member 10 by cams 13 carried by lever arms 14 suitably pivoted on the plate 12. The pivot bolts for the levers 14 extend through a suitable slot 12 in the plate 12, so that the cams 13 may be moved relatively toward and away from each other.

As above described in the embodiment of the invention illustrated in the accompanying drawings, the tube clamp cams 13 are adapted to be manually operated, but it will be evident that said cams might be actuated by fluid pressure in a manner similar to other movable elements of the machine hereinafter referred to.

In operation, the tube to be bent is supchine in Fi 1, is engaged b ported upon a suitable mandrel, hereinafter more particulary described, including a rigid stem or shank held stationary at one side of the rotar carrier 9, and between the clamping mem ers 10, 11.. The end of the tube, which projects beyond the periphery of the carrier 9 at the right hand side of the masuitable jaws carried by an arm 15, which 1s clamped about a centrally arranged depending hub 9' on the carrier 9.

This clamp, as shown particularly in Figs. 1, 2, 5 and 5 comprises two jaws 15, 15", pivotally mounted at 15 on a member that is supported at the outer end of the arm 15. The jaws are moved into and held in engaging1 relation with a tube by a screw 16 carrie in a pivotally mounted holder 16" and having at its outer end an arm or hand piece 16 by which it may be rotated. The support for the jaws 15, 15", has a de nding expandible, tubular, shank 17, whic has a pivotal bearing in an aperture adjacent the outer end of the arm 15. A nut 17 arranged within the expanding shank 17 and engaged by a screw 17 acts to effect close en agement of the shank 17 with the arm 15 an yet per: mits of angular adjustment of the pipe engaging jaws 15, 15'', relative to said arm, if deslred.

The particular arrangement or construction and relation of the jaws 15', 15", de-

scribed and illustrated is of considerable importance. It will be seen that by loosening the screw 16 the holder 16" may be swung about its pivotal support, and the jaws 15, 15 turned on the axis 15 so that the bent tube will be entirellyq released and can be lifted away from t e clamp without any turning thereof.

The end of the arm 15 which embraces the hub 9 of the carrier 9 is split, as shown in Fig. 1, and the two sections are drawn tightly together by means of a suitable screw bolt. Therefore, said arm may be adjusted about the hub of the rotary carrier 9, and the jaws 15", 15, carried by said arm, c0rrespondingly adjusted so as to properly receive tubes of different diameters. As before stated, the forms or tube clamp members 10 and 11 are detachable, and similar forms ada ted to properly engage tubes of different 'ameters may be substituted for the one shown.

lVhen such substitution is effected, it is necessary to adjust the clamping jaws at the outer end of the arm 15 to pro erly align said aws with the tube grasped etween the clamp members 10 and 11. If it is desired to make such a change the proper forms of clamps 10 and 11 are attached to the carrier 9, a tube placed in position thereagainst and the adjustable clam 11 moved to properly enga e the tube. e screw connecting the mem ers of the arm 15 adjacent the hub of the rotary carrier being loosened, said. arm is properly adjusted about said hub into its correct position with relatlon to the tube and clamps 10, 11, and the jaws 15, 15", thereon engaged with the tube. The screw 17 and the screw connecting the sections of the arm 15 at the hub 9 are then tightened and the several parts thus secured in the new and proper relation for operation. 7

The relatively stationary tube clamp member 10 is mounted on the carrier 9, as before described, and comprises a hub-like portion which is fitted about the upper end of the shaft 4 and a longitudinally extending section in one face of which is formed a semi-circular groove or channel 10* that 1s continued about the hub-like portion of the clamp member. The other member 11 of the clamp has a correspondingly shaped groove in its face adjacent the member 10 so that when the two members are brought together by the action of the cam levers 14, they will closely surround the tube to be bent. Any danger of the action of the cams 13 causing the tube clamps to engage the tube in such manner as to effect a colla sing thereof is avoided by inserting a sultable mandrel in the tube.

During the bending operation the tube is supported by suclrmandrel which is adjustably connected with a reciprocating carrier mounted in hearings on the machine at one side of the rotary carrier 9 in substantial alignment with the space between the tube clamping members 10, 1-1, when in the position shown in Fig. 1.

The mandrel shown comprises a rigid stem 18 which is connected to the reciprocating carrier, as will be hereinafter described, and a flexible extension that projects into the tube and between the clamp members 10, 11, beyond the axis of the shaft 4 so that it is adapted to flex with the tube as it is bent about the shaft 4 as the carrier 9 is rotated.

In the form of mandrel shown particularly in Figs. 13 to 15, the flexible section is formed by several series of links 19 pivotally connected by rivets 19 and terminates in a hemispherical head 19". The flexible section is gradually reduced'slightly in diameter from the solid section 18 to within a short distance from the head 19 and then gradually increases slightly in diameter to such ball end. Preferably, the several links are slightly ground off on one side as at 19 so that when the mandrel is bent it will be slightly flattened on its outer periphery, or on the convex face of the bent mandrel.

The other end of the mandrel stem 18 from that to which the flexible section is secured has a reduced threaded portion which (see Fig. 5) is screwed into a bushing 90 mounted in the mandrelcarrier 20. This carrier is supported between guide rails 21 carried by a member 22 mounted on a bracket 23 adjust-ably connected with the top plate 24 of the main supporting pedestal. i

A shown, four bolts 23 hold the bracket 23 to the top plate of the pedestal, said bolts extending through slots in the plate 24 so that, as above stated, the bracket and parts carried thereby may be adjusted laterally. The necessity for this adjustment is that when a change of the tube clamps 10, 11 is made to adapt the machine to work on tubes of a different diameter, it is, of course, necessary to eifect'a lateral movement of the plate 23 so that the axes of the mandrel and tube will be in accurate alignment when the parts are positioned as in Fig. 1.

The threaded end of the mandrel is secured within the bushing of the carrier 20 by a lock nut 20". The carrier and mandrel connected thereto are adjusted longitudinally of the guide-way in the member 22 by means of a feed screw 25 which is connected at one end to the carrier and extends into engagement with an interiorly threaded feed nut 25 mounted in a bearing on the member 22 and to the outer end of which is secured a gear 25 As this gear is rotated, by means to be hereinafter more particularly described, the mandrel carrier and mandrel will be moved longitudinally into proper relation to the tube clamping members on the carrier 9.

The mandrel extends through a passage formed in a tension guide 26 supported by a plate 26 that is adjustably connected with the mandrel carrier 20. The passage through the tension guide is sufficiently large to permit the entrance thereinto, about the man rel stem 18, of the end of the tube which is to be bent. The bolts 26 which connect the plate 26 with the carrier 20 extend through suitable slots formed in said plate and by means of a screw 20 hearing against the rear end of the plate 26, said plate and the tension guide may be adjusted relative to the mandrel and tube clamps 1U, 11 so as to fix and determine the distance that the mandrel can be moved toward the" axis of the shaft 4 about which the tube is to be bent, said movement being effected by the feed screw 25. The end of the tension guide 26 is so formed that it will contact closely with the hub of the tube clamp member 10 on the carrier 9, thus limiting the movement of the mandrel in that direction. Such contact occurs just after the clutch controlling movement of the feed screw is thrown out as hereinafter described.

As shown, the mandrel stem or body 18 is provided at diametrically opposite points with short projecting studs or pins 18 which serve as stops to endwise movement of the tube which is slipped over the mandrel.

Preferably, the mandrel carrier 20 and the plate 26 which carries the tension guide- 26 are held from relative lateral movement by a key 26 which is-fitted-in aligned rooves 20 and 26 formed in the adjacent aces of the carrier 20 and plate 26.

' When the machine is operating, the tension guide 26 is held ri id and against the abutment provided by the hub-like portion of the clamp member 10 on the plate 9 by a presser foot 27 which has a sliding bearing in a housing 28 suitably supported from the main frame and isconnected throu 'h a toggle 27 and a connecting rod with 0. diaphragm arranged in a fluid pressure chamber 29. The suppl of fluid for operating the diaphragm in t e chamber 29 is automatically controlled, as will be hereinafter more particularly described, and when fluid is supplied to said chamber the toggle 27" is spread to force the presser foot or plunger 27 into contact with the tension guide 26 and check relative longitudinal movement between the tube and mandrel as the carrier 9 is rotated.

The gear 25", which controls longitudinal movement of the mandrel carrier and mandrel, meshes with a gear 30 which is keyed to a sleeve surrounding a stud that is carried by a plate secured to the bracket 23. To said sleeve is also secured a bevel gear 31 that meshes with two bcvels 32, 32*, on a countershaft 33, mounted in suitable bearings on the aforesaid bracket 23, carried by the pedestal top plate 241. The shaft 33 is constantly rotated by a suitable belt, not shown, enga ing a band wheel 33"; and on said shaft a jacent each of the bevel gears 32, 32, is mounted a suitable clutch mechanism34, 34, by means of which said gears 32, 32*, can be alternately connected with the shaft and through the gears 31, 30 and 25", caused to reciprocate the mandrel carrier and mandrel as required.

The clutches 34, 34, are simultaneously actuated by shifter arms 35, 35, mounted on a shifter rod 36, which is supported on the bracket 23. At one end the shifter rod 36 is connected to a manually operable shift lever 36. When the clutch 34 is engaged with the shaft 33 the feed screw nut 5 will be turned to feed the mandrel carrier and mandrel toward the shaft 4 and into operative position, whereas when the clutch 34 is engaged with the shaft the feed screw nut 25 will be oppositely rotated and act to Withdraw the mandrel from the tension guide 26 and the tube in which it may be 1nserted.

Means are provided whereby independent of any movement of the manually operable lever 36, the shifter rod 36 will be automatically shifted as the mandrel carrierapproachcs the limit of its reei rocating movement in either direction. uch means, in the embodiment of the invention illustrated,

is pivotally connected 'at 41 to the bracket 22 and carries a pin 42 which is alternatelv engaged by the stop dogs 37, 38, on the man: drel carrier, so as to disengage whichever clutch 34; 34 is operative at the limit of vmovement of the mandrel and mandrel carrier in either direction. In case the momentum of the arts should tend to continue movement of t e mandrel toward the tube clamps after the clutch 34 is disenga ed, such movement will be properly checke b contact of the tension guide 26 with the hu of the clamp member 10.

On the main power shaft 7 are mounted two loose pulleys 50, 51, which are adapted 'to be constantly rotated by power belts, not shown, and associated with each of these pulleys is a clutch 51", by operation of which the direction of rotation of the shaft may be controlled. Said clutches are simultaneously operated through a rod 52 which is connected with the starting lever53. The lever 53 is pivotall mounted on a bracket extending lateral y from the supporting pedestal (see Fig. 3). The upper portion of the lever 53 is provided with a laterally projecting angular extension 53" which terminates in a handle 53 that is situated some distance in front of the machine.

Means are provided whereby it is impossible to start the machine and effect rotation of the carrier 9 and the tube en aging members carried thereby .until the p unger 27 is in proper relation to the tension guide 26. Such means includes a lock normally preventing outward movement of the startmg lever 53 and starting of the machine, and

the disengagement of which automatically opens a valve in a conduit for sup lying fluid, under pressure, to the diaphragm chamber 29. The particular locking means shown is a block or dog 54 which is adjustably mounted on a lever 55 that is carried by a short shaft 56 mounted in a suitable bearing on an ear 24" depending from the top plate of the supporting frame or pedestal. At its outer end the lever 55 is rovided witha handle 55, by means of whic it may be raised to lift the dog or block 54 from the ath of the starting lever 53.

T e shaft 56 is also provided with a short arm 57 from which extends a rod 58, the free end of which passes through a lever 59 mounted in a suitable yoke-like frame 60 on the head of a valve casin 61 forming part of a system of piping For supplying fluid under pressure. A sleeve 58 adjustably mounted on the rod 58 bears against the lever 59, and by adjustment of such sleeve the actuation of the valve in the casing 61 may be accurately controlled. \Vhen the lever is raised to permit operation of the starting lever 53. it will be seen that the valve in casing 61 will be opened and fluid under pressure supplied to the diaphragm chamber 29", which, as before pointed out. will extend the members of the toggle 27 and move the presser foot 27 into proper engagement with the tension guide 26.

Fig. 19 illustrates the positions of the sevbeen disengaged and the tension guide engaged by the presser foot 27, as above described, forward movement of the lever 53 will, through the rod '52, cause engagement of clutch 50 with the driving shaft-7, and

the worm 6 and gear 5 will rotate the disk carrier 9 in the direction of the arrow in Figs. 1 and 4. Such rotary movement will carry the portion of the tube engaged by the clamping members 10, 11, about the axis of the shaft 4 and will etfect a longitudinal movement or slip of the tube through the tension guide 26. The pressure exerted on tension guide 26 by the presser foot 27 which may be varied as desired by means of the adjusting nuts 27 and 27, will prevent such longitudinal movement of the tube through the tension guide as would result in wrinkling the inner periphery of the bend or cause rupture of the tube. The mandrel being held stationary by reason of the tension guide 26 abutting the end of the tube clamp 10 adjacent the shaft 4, the tube end being treated will be drawn away from the stops 18 and will slip over the mandrel as the bending continues.

As the rotating carrier 9 advances in the direction of the arrow in Fi 1, the flex- ,'ble portion of the mandrel is bent with the tube about the hub-like end of the tube clamp member 10, and the tube may thus be bent to any desired angle.

Movement of the rotating carrier may be checked at any time by returning the starting lever to stop position in which the rod 52 will disengage the clutch 50, such stopping being assisted by a suitable brake, hereinafter more particularly referred to.

Means are provided, as illustrated in Figs. 1 and 10, whereby angular movement of the carrier 9 may be automatically checked, as desired, and the mandrel carrier moved to effect automatic withdrawal of the mandrel from the bent tube. Pivotally connected to the outer end of the arm 15 is a pawl 62 that terminates ina depending lug 62. This pawl is normallyprojected from the end of the arm 15 by a spring'pressed plug 62 mounted in a socket in the arm 15. Movement of the pawl, relative to the arm, is limited by a pin and slot connection, as shown particularly in Fi s. land 9 to 11 inclusive.

an the shifter rod 36, controlling, as heretofore pointed out, the clutches 34, 34, of the mandrel feed mechanism are secured two dogs 64, 64. As the carrier arm 15 approaches the limit of its turning movement the depending lug 62, at the free end of the pawl 62, will contact with the dog 64 and move the rod 36 longitudinall to engage the clutch 34 with the sha t 33 and thus initiate movement of the feed screw 25 in a direction towithdraw the mandrel from the tube. As the dog 64 is shifted to the dotted line position shown in Fig. 11, a stationary cam 65 will contact with the awl lug 62* and move the pawl against t e action of the spring plug 62 away from the dog 64.

Simultaneously, with the engagement of the shifter dog 64 by the pawl 62, as above described, the carrier arm 15 engages the end of a shifter rod 66 which extends transversely across the machine and has one end engaging one arm of a lever 67, the other" arm of which, through an adjustable rod 68, is connected to the starting lever 53. Therefore, as said shifter arm 66 is operated the starting lever is returned to stop position, during which movement the'fluid pressure valve in casing 61 is closed, and, by escape of pressure from the chamber 29*, the toggle 27 is permitted to drop and withdraw the presser foot 27 from the tension guide 26. I

When the shifter rod 36 is moved, as above described, by the pawl 62, said rod is caused to actuate alever 7O controlling a valve in the fluid pressure system connecting a branch 71 with the main supply pipe, said branch 71 in turn being connected to a chamber 72 containing a piston, the stem of which is suitably connected with a toggle 73. This toggle is also connected with aslide 74, the forward end of which is curved to conform to the bent surface of the tube. Therefore, durin the period thatthe mandrel is being withdrawn and the pressure on the tension guide 26 is released, said sliding member 74 is maintained in contact with the bent tube. Such engagment of the member 74 with the bent tube prevents distortion or rupture thereof,

as the mandrel is withdrawn. The lever 70 i shaft and power means for withdrawing the mandrel from a tube, or in its forward position,-the valve controlling movement of slide 7 4 will also be actuated to project said slide from itscasing. Further, the lever 70 may be independently moved manually to effect such movement of the slide 7 4.

Movement of the starting lever 53, to stop position, also effects operation of a brake by means of which rotation of the carrier 9 is checked as said starting lever reaches stop position.

The brake comprises brake bands 80, 81, (shown particularly in 'Figs. 2, 4, 16 and 17) which are bolted to a portionpf the supporting frame at one end and partially embrace a brake wheel or drum 82 mounted on the end of the worm shaft 7. The bands 80, 81, are adapted to be engaged wit! the brake wheel to check rotation of the worm parts actuated thereby, bya cam 83 which 1s mounted on a short shaft 84 from which projects an arm carrying a weight 85. The free ends of the brake bands are embraced by a yoke 84 which is sup ported by the shaft 84. The weight 85 normall holds the parts in the position shown 1n Fig. 16 in which the brake is released. An arm 86. attached to and extending downwardl from the starting lever 53, is provided wit a lateral extension 87 having a cam portion which is adapted to cooperate with the arm carrying the weight 85, so that as the starting lever is returned to stop position the cam on the arm 87 will lift said weight carrying arm, actuate the cam 83, and apply the brake.

By moving the starting lever 53 toward the machine from the stop position the rod 52 will be caused to connect the drive pulley 51 to the worm drive shaft 7 and thus produce a reverse rotation of the shaft 4. and rotary carrier 9. When, during this movement, the lug 62 on the awl 62 engages the dog 64 on the shi ter rod 36,

' the latter will be moved to effect disengagement of the clutch 34 and connect the clutch 34 to the shaft 33 so that the mandrel feed screw 25 will be turned to feed the mandrel forward into the position shown in Fig. 1 to receive another tube. It will be understood that the bent tube is to be removed from the machine, as hereinafter described, rior to moving the starting lever the machine to effect such re verse movement of the rotary carrier 9.

As the pawl 62, b engaging with the 7 dog 64, moves the s ift red, as last described, such: pawl will come against a stationary cam 65 and be thereby disengaged from the dog 64" so that the return movement of the arm 15 will not be interfered with. v

'The worm gear 5 is provided with an upwardly projecting pin 5 which is adapted to cooperate with a dog 52 secured on the shift rod '52 whereby, as the tube clamp member 10 comes into proper alignment with the tension guide 26, the rod 52 will be moved longitudinally to disengage both of the clutches on the shaft 7. Such movement will restore the starting lever to stop position, and, through the arm 86 and cam 83, effect an application of the brake as above described. A pawl 88 is adapted to cooperate with a collar 89 on the clutch shift rod 52 when said rod is in position to disengage both clutches 50*, 51, and the starting lever is in stop position. This retains the rod 52 temporarily in neutral position and eliminates danger of the machine being started accidentally and prematurely.

While the operation of the machine illus trated in the drawings has been generally described in the foregoing pages, it may be briefly recapitulated as follows The tube '1 to be bent is preferably, though not necessarily, cutdiagonally at that end which is to fit over the mandrel, as shown in Figs. 1 and 9, for example, and initially may havea solid core 100 inserted in the portion thereof which is to be grasped by the jaws 1'5, 15", of the swinging arm. 15., for the purpose of preventing cross sectional collapse of the tube when clamped by said jaws. The tube is then positioned as shown in Fig. 1, being shoved through the open jaws 15", 15", between the clamping members 10, 11, of the carrier 9, overthe flexible section, of the mandrel and into the tension guide member 26 until the end thereof abuts the stop pin or pins 18. The screw 16 is then actuated to cause the jaws'15, 15, to closely embrace the tube. The cam levers 13, 14, or equivalent means, are actuated to movethe laterally slidable tube clamp 11 into engagement with the tube, and the locking lever 55 is raised to release the starting lever 53. It will be recalled that raising the locking lever in this manner acts through the means controlling the valve 61 to supply fluid under prewire to the diaphragm chamber 29,. and thus causes the presser foot 27 to bear against the tension guide 26.

The starting lever 53 is then moved, causing shift rod 52 to effect engagement of the clutch 50 with the power shaft 7 in such manner that the worm 6 and worm wheel 5 will rotate the shaft 4 and carrier 9 in the direction of the arrow in Fig. 1. Rotaposition to engage the end of the shifter rod 66 the starting lever 53 will be returned to normal stop position, and rotation of the carrier 9, and parts secured thereto checked by the application of the brake as previously described. As the arm 15 thus approaches the termination of its swinging movement in the directhm of the arrow, the pawl 62 thereon will actuate the shifter rod 36 through the dog 64-, to effect engagement of the clutch 34 with the mandrel food drive shaft 33 so that the screw 25 will be turned to withdraw the. mandrel from the tube. The ball end 19 of the mandrel is exactly circular in cross section and of the full 'diamcter of the tube so that, as the mandrel is withdrawn, such ball will correct any lateral distortion of the tube.

As the starting lever is returned to stop position by the shifter rod 66 and lever 67 the locking lever 55 will fall, thus actuating the valve 61 and releasing the pressure of the presser foot 27 against the tension guide 26.

Movement of the shifter rod 36, by pawl 62 and dog 64 will actuate the lever and valve controlled thereby and effect communication between the fluid lwessnre main and cylinder72 so that the toggle 73 will be operated to carry theoutside movable form 74 against the portion of the tube adjacent the clamp members 10, 11. As the mandrel carrier moves to the left in Fig. 1 to withdraw the mandrel, as just described, the stop 37 will engage the pin 42 and rock the lever 40, at the termination of the return movement of the feed screw 25, to impart a slight movement to the rod 36 to disengage clutch 34 therefrom and allow these parts to come to rest. This latter movement of the shifter rod 36 also cuts off the supply of fluid to the cylinder 72 and permits the toggle 73 to drop and withdraw the member 74 from engagement with the tube.

The jaws of the clamp at the outer end of the arm.- 15 are then released by turning the screw 16 after which the cams 13 are moved to release the clamp member 11 and permit the same to be moved away from the tube and clamp member 10. The bent tube, together with the solid core therein. is then removed from the machine, and the core manually withdrawn from the tube.

Moving the starting lever 53 toward the machine sufficiently to cause the shifter rod 52 to effect engagement of the reverse clutch 51 with the worm shaft 7 will cause the carrier 9 and parts connected therewith, to move in a direction 0 posite to that indicated by the arrow in ig. 1 to position to permit another tube to be inserted for bending. During the first portion of such rearward movement of the arm 15 the pawl 62 will engage the dog 64 on the shifter rod 36 and effect engagement, of the clutch,

which causes the feed screw 25 to turn to feed the mandrel toward the shaft 4. As the mandrel approaches the shaft 4 the stop 38 on the mandrel carrier will engage the pin 42, and, through the lever 40. move the shifter 36 to disconnect both clutches from the mandrel drive shaft; and, at the same time, as the tube clamp 10 comes into proper alignment with the tension guide 26, the pin 5* on the worm gear 5, will, through the collar 52, move the rod 62 to release the .worm. shaft 7 from the clutch 51." and restore the starting lever to stop position, such movement of the starting lever acting to apply the brake as before described.

By the method followed with the machine. hereinbefore described, the tube is permitted to flatten but slightly over the flattened portion of the mandrel, and, therefore, as very little stretching of the tube in cross section is required in restoringit to normal or circular cross section, which is effected by the ball or head 19 of the mandrel tening of the tube which occurs during the bending operation, and the restoring of the bent section to normal cross sectional form as the mandrel is withdrawn.

When the tube has been completely bent, as shown in Fig. 22, it will be seen that the wall of thebend is slightly flattened. the-distance between the dotted and full lines indicating the-extent of such flattening. As the mandrel is withdrawn, this flatten ing, as shown in Fig. 23, is gradually eliminated. and the normal cross sectional form of the tube restored by the spherical head 19 of the mandrel. I

In Figs. 24 to 28. there is illustrated a slightly modified form of mandrel which may be employed. In this form the mandrel comprises the rigid stem or shank portion .18, a head 19, and an intermediate flexible section composed of superposed plates 19, 19, 19', 19 and 19 which are connected by suitable pivot pins. The head 19 includes a body'portion which is provided, at one end, with grooves to receive the adjacent plates composing the flexible section. and with a reduced portion 19 from which projects a threaded stud 19. A ring 19 is threaded about the portion 19, being free Ill to rotate thereon, and is held against the As before stated, and as shown in the drawings, it is prefcrred'to initally cut the end of the tube which extends over the mandrel at an angle. After the tube has been bent, the projecting portion of this angular cut end of the tube is distributed throughout the wall of the tube on the outer periphery, thus more nearly maintaining'the original thickness of the tube wall than was possible with the methods heretofore employed. Cutting the -end of the tube on an angle provides a projecting end which is distributed during the bending operation and efl'ects a considerable saving of material that would be waste if the end of the tube was initially square or at right angles to thelength thereof. p

In the foregoing description of the operation of the machine it has been assumed that a complete return bend, such as shown in Fig. 10, is to be produced. In case it is desired to bend the tube to an angle less than that shown in Fig. 10, for example, to an angle of ninety (90) degrees, an arm 90 (shown in dotted lines in Figure 1) is detachably connected to the rotary carrier 9,

said arm being rovided at its outer end with a pawl similar to the pawl 62 at the outer end of the arm 15. With this arrangement it will be understood that the arm 90 will actuate the shifter 36 when the arm 15 has reached the position B indicated in dotted lines in Fig. 1. The arm 90 is, of course, removed when it is desired to form complete return bends in which operation, as above described, the pawl 62 on the arm 15 controls actuation of the shifters 36 and 66. The arm 90 may be applied at any suitable position on the carrier 9, according to the particular angle to which it is desired to end the pipe.

As hereinbefore described, and as illustrated, the arm 15 is not only adapted to con trol proper actuation of the power devices when the machine is employed for effecting a bending through 180 ut as supporting the tube jaws 15, 15. It will be evident, however, that said jaws may be supported inde ndently of the arm, and the latter mere y constitute a means for shifting theclutches and efiecting stopping of the machine when a tube has been bent to any desired, predetermined, extent.

We claim:

1. In a tube bending machine, the combination of a pivotallymounted tube carrier,

a mandrel having a flexible section, means for moving the mandrel to and from a posi- 2. In a tube bending machine, the combination of a pivotally mounted tube carrier, a

mandrel having a flexible section adapted to be positioned with the'flexible section within the end of a tube in the carrier adjacent the axis of the latter, power devices for moving the tube carrier about its axis, bending the tube and flexible section of the mandrel therein, means for withdrawing the mandrel from the tube at the termination of the turning movement of the carrier, and automatically acting means-for applying pressure to the bent tube adjacent said axis while the mandrel is being withdrawn.

3. In a tube bending machine, the combi nation of a pivotally mounted tube carrier, a mandrel having a flexible section, means for positively moving the mandrel to and from a postion where the flexible section is within the end of a tube in the carrier adjacent the axis of the latter, power devices for moving the tube carrier about its pivot, means for automatically disconnecting the tube carrier and power devices when the carrier has been turned through a predetermined angle, means for automatically withdrawing the mandrel from thetube when the turning movement of the carrier ceases, and means for appl ing pressure to the bent tube section as t e mandrel is being withdrawn.

4. In a tube bending machine, the combination of a pivotally mounted tube clamp, a mandrel having a flexible section adapted to be positioned in the end of a tube engaged by the clamp adjacent the axis of the latter, means for exerting pressure on the tube to resist movement thereof longitudinally of the mandrel, power devices for moving the tube clamp about its pivot, means for automatically disconnecting the power devices and tube clamp when the latter has been turned through a predetermined angle, and 1 means for automatically withdrawing the mandrel from the bent tube when the clamp and ower devices are disconnected.

5, n a tube bending machine, the combination of a pivotally mounted tube clam a mandrel having a flexible section adapted to be positioned in the end of a tube engaged by the clamp adjacent the axis of the latter, means for exertinglpressure on the tube to resist movement 1; ereof longitudinally of 

